The field of art to which this invention pertains includes that of hose couplings for attachment with fluid conductors.
Fittings are used as connectors in order to link fluid conductors with each other. Fittings generally include a tubular element, or tube, having two ends. The first tube end has an outer surface designed to maintain a swivel nut in a predetermined axial location while allowing the swivel nut to rotate. The second tube end has an outer surface which affixedly retains a tubular shell that circumferentially surrounds this end.
The usually externally hexagonally shaped swivel nut typically has internal threads that serve for attachment to the male port end of a fluid conductor. The swivel nut is sealingly fastened onto the noted male port end with a torquing device to a predetermined tightness. During this fastening process the inner end surface of the swivel nut comes into contact with its adjoining tube end such that friction between the two components will cause the entire tube to rotate with the swivel nut. Typically, prior art fittings include a hexagonal holding surface provided on the tube itself so that the user can hold the tube, via this holding surface, in a static or fixed position while tightening the swivel nut. By virtue of holding the tube in a static position, the desired angle, or orientation of the fitting is maintained. A cost disadvantage associated with the tube holding surface is that this entails another machining or forming process in order to provide such a hexagonal surface on an otherwise cylindrical tube.
The second end of the tube has an end portion that is adapted to be inserted into a conduit. The surrounding shell, which is attached to the second end of the tube, surrounds the conduit. The conduit, or course, is the fluid conductor that is used to transfer fluid from one location to another. Typically, this conduit is flexible so that the fluid can be transferred in multiple directions or angulations without the awkward bending of a rigid pipe. In order to attach the conduit to the fitting, the shell is inwardly deformed so that the intermediate conduit portion is compressed between the shell and the tube.
Rather than providing the tube element with a hexagonally-shaped outer surface, some prior art fittings provide a hexagonally-shaped holding surface on the shell itself. Examples of such a shell are shown in U.S. Pat. No. 4,804,212 to Vyse, which is also assigned to the assignee of the present invention, U.S. Pat. No. 5,317,799 to Chapman et al., and in published PCT Application No. WO 94/18487 to Shiery. These prior art references have hexagonal outer surfaces on the shell which are formed during the inward deformation, or crimping, of the shell onto the conduit. The disadvantage of this type of shell is that the shell can still rotate relative to the conduit and tube while it is being held.
Shells can be fixedly attached to the tube by several methods. As is well known in the art, the inner axial end of the shell can be inwardly deformed, or crimped, onto the tube so that it is compressively attached. Other methods include radially compressing an inwardly directed shoulder of the shell into an annular groove in the tube. This is shown in the previously mentioned U.S. Pat. No. 4,804,212 to Vyse.
Another method of affixing the shell to the tube includes axially compressing an inwardly directed shoulder of the shell between two radially outwardly extending protuberant surfaces, such as annularly formed beads. Examples of such an attachment are shown in U.S. Pat. No. 3,924,883 to Frank; U.S. Pat. No. 6,270,126 B1 to Juedes; and Japanese Pat. No. 5-118483 to Funato. Although these constructions may axially limit the movement of the shell relative to the tube, a disadvantage arises when the tube starts to rotate with the nut during its torquing. The installer will try to hold the shell static in order to prevent its rotation and linear misalignment. Although the shell has been inwardly compressed onto the conduit, it may still rotate relative to the conduit (and/or tube) if its contact with the tube does not prevent same. For example, if the inner surface of the shell shoulder is circular, the shell may be able to rotate relative to a cylindrical tube.
The present invention provides a coupling for attachment to a conduit. The coupling has a longitudinal axis and is comprised of a tube and an attached tubular shell. This invention overcomes the obstacle of shell rotation relative to the tube, and tube movement during fixed attachment of the coupling to a mating end.
A feature of the present invention is to provide coupling where the tube has a first end, a second end and a longitudinal bore extending from the first end to the second end which is adapted for insertion into the conduit. The tube further includes an intermediate portion between the first and second ends having spaced first and second radially outwardly extending annular beads. The coupling is further comprised of a tubular shell having a first portion and a second portion. The first portion is axially confined between the first and second annular beads and has an inner surface with a first axial end and a second axial end, wherein one of the first and the second inner axial ends has a non-rounded shape. The shell second portion extends axially from the first portion to a free end and has an inner surface spaced radially and coaxially outwardly of the exterior of the tube second end to define an annular recess therebetween and is adapted to be inwardly deformed toward the tube second end.
A further feature of the noted coupling includes having at least one of the first and second non-rounded shaped inner surface axial ends being an elliptical shaped undercut located at the proximal end of the first portion. Another feature includes having an abutting portion of the first bead being permanently deformed into a similar shape as the adjoining elliptical shaped undercut as a result of formation of the second bead.
Still another feature of the noted coupling has at least an axial portion of the tube being other than straight. A further feature of the noted coupling has the tubular shell first portion having an exterior surface with a plurality of angularly spaced flat portions forming retaining flats.
Another feature of the noted coupling has the tubular shell first portion being comprised of two parts, a first surrounding part and an annular insert. The surrounding part has a longitudinal segment extending from the tubular shell second portion and a substantially radial segment having an end abutting the outer surface of the tube with an outer surface in contact with the first radially outwardly extending annular bead. The annular insert is axially symmetrical and has an outer surface in contact with the inner surface of the longitudinal segment. The annular insert further has a first annular surface in contact with the inner surface of the radial segment, and a second annular surface in contact with the second radially outwardly extending annular bead.
Still yet another feature of the noted coupling has the at least one non-rounded shaped inner surface of the tubular shell preventing the shell from rotating relative to the tube as a result of the formation of the second bead. The formation causes the permanent deformation of the abutting portion of the adjacent one of said first and second beads into a similar or conforming shape with said non-rounded shaped inner surface.